525SC Carbs
 

I have a couple questions if anyone can help regarding Merc 1050 Dominator Carbs that were original equipment on the 525SCs:

1. What is stock merc jetting and PV on these carbs?

2. How is the boost referenced power valve achieved and how can I tell if some 1050 blue carbs are actually blower carbs?

BT

Jets should be #98 all around. The carb is not boost refered, if I remember correctly PW is 6.5.

bl

98's and 6.5's is correct. Stock jetting is rich. Not sure about the boost referencing. Mine did have a hose and pvc valve going to the carb base. My jetting was stock with 98's even with 7.5-8#'s of boost and it was fine. Went up about 4 sizes when added a roller cam.

Thanks for the replies. It sounds like merc jetted like there was no power valves thinking they will never open anyway.

BT

Blue Thunder- What jetting was in your carb? 98's? .... Does your carb have Power valves or not?


I have re-jetted many of these engines. I would run 93 jets square with a 6.5 power valve in the primary and 5.5 in the secondary. From stock jetting , on average the boat will pick up about 2 sometimes 3 MPH. Mercury likes to flood engines with fuel. I hope this helps. :cool-smiley-027:

They have 98s square and 6.5 front and back. They were supposed to be stock and I just wanted to make sure. I was curious why merc would choose not to do the boost referencing? Do you boost reference MrHP when lowering the jets and PVs?

I have boost referenced before, The carbs are under vacuum , running power valves is just fine. Run the jetting I stated above, if want want to start a bit richer install 94's. The engines will wake up!:D The other thing I want you to do is set the float levels with the bowl off. Invert the bowl (up side down) and with a pin gauge or clean drill bit, set the floats at 23/64 or .3594 measured in the center of the float/bowl. This will correctly set the floats so they are not too low or too high. The gauge should just slip under the top of the float.

Thanks much MrHP. I'll take that advise.

BT :cool-smiley-011:

Would the same jetting apply to a 525sc that has an intercooler? I have one and right now it is jetted richer, plugs read rich=safe. I know there is room for improvement.

Anybody??